1. Field of the Invention
The invention relates to railway rolling stock and consists particularly in a radial axle truck having improved means for steering the axles and damping hunting movements and a brake system compatible with steering movements of the axles.
2. The Prior Art
Radial axle trucks of the prior art have generally been of the outboard bearing type and in most of those in which steering of the individual axles was provided by the differential effect of conically profiled treads on curved track, resistance to longitudinal movements of the axles with respect to the truck frame was provided by longitudinally acting springs between the outboard axle bearings and the outboard side members of the truck frames or outboard truck side frame. With this location of the longitudinally acting springs, springs stiff enough to maintain the axles in relatively fixed positions longitudinally of the truck during movements on tangent track would offer excessive resistance as a couple to turning or yawing movements of the axle for steering on curved track where the truck side frames are widely spaced apart as on standard or broad gauge cars because of the relatively great spacing transversely of the truck of the longitudinally acting springs and the correspondingly long moment arm through which these springs would act as a couple to oppose turning movements of the axle. This problem would of course increase in seriousness in proportion to the track gauge but would undoubtedly be very serious on all gauges including and exceeding the 4 foot 81/2 inch gauge which is standard in the United States, Great Britain and most of Western Europe and increasingly serious on broad gauges, such as the 5 foot gauge as used in the U.S.S.R., the 5 foot 3 inch gauge used in Ireland and elsewhere and the 5 foot 6 inch gauge used in Spain and elsewhere.
In such trucks any diagonal links, bars or rods connecting diagonally opposite axle bearings would have to be bent to clear the wheels, thus requiring heavier links than would be required if straight links could be used.
Because of the steering movements of the axles and the consequent variations in longitudinal spacing between the wheels at the respective sides of the truck, in radial axle trucks of the prior art individual brake rigging was commonly provided for the respective axles and was pivotable therewith.